Literal integer numbers can appear in Java programs in base ten, hexadecimal, and octal forms : Literal « Java Source And Data Type « SCJP

1. SCJP
2. Java Source And Data Type
3. Literal

public class MainClass {
  public static void main(String[] argv) {
    int n = 42;
    long j = 4; // appending L or l makes it a long
    long k = 0xFFFFFFL;
    byte b2 = 010; // an octal literal
    double f2 = 1.023; // double is assumed
    float d2 = 1.023F; // F or f makes it a float

    System.out.println(n);
    System.out.println(j);
    System.out.println(k);
    System.out.println(b2);

    System.out.println(f2);
    System.out.println(d2);
  }
}

42
4
16777215
8
1.023
1.023